This invention relates to a tamper-evident closure.
Many types of such closures are known. Their purpose is to ensure that once a closure has been opened it cannot then be re-closed without it being apparent that it has previously been opened. Such closures are widely used in connection with containers for products such as medicines or foods to prevent interference with the contents of the containers after they have been closed by the original manufacturer and packer.
The invention more specifically relates to a doubly tamper-evident closure. By this it is meant a closure which, after opening, can be re-closed, with it being evident whether the closure is in its initial condition, or whether it has been opened once and re-closed, or whether it has been opened after re-closure. By way of example, one context where a doubly tamper-evident closure would be desirable is in the case of certain pharmaceutical products which may be supplied by the manufacturer to a user, such as a hospital, in one form (e.g. as a powder) and which are then converted by the user to a second form (for example converted to a solution by adding water) to be stored for subsequent administration to patients. This is the case, for example, with certain antibiotics. In such a case it would be desirable for the container initially to be tamper-evident so that the hospital knows that the container it receives has not been tampered with on its way from the manufacturer, and then, after the container has been opened, water added, and the container re-closed, for it again to be tamper-evident so that a nurse or other person administering the solution to a patient knows that the solution has not been tampered with since it was originally prepared.
The invention particularly concerns a closure of the type which consists of two parts, one being pivotally or hingedly connected to the other. Closures of this type which are singly tamper-evident are well known, for example from U.S. Pat. Nos. 4,815,618 and 4,838,441. Another closure of this type is known from U.S. Pat. No. 4,795,044, this closure including a first tamper indicating device between one part and the container to which the closure is fitted, and a second tamper-evident device between the two parts, the second tamper evident device being in the form of a locking ring which is hingedly connected to the said one part. However, this closure is not doubly tamper-evident as between the two parts thereof. The first tamper-evident device relates only to the connection between the closure and the container.